Discuss the factors that may affect the frictional forces acting on the block (e.g. load on *the block, surface area in contact with the bench, type of the surfaces in contact …)

Attach a force meter to a block at rest on the bench. Pull the force meter and slowly increase *the force until the block just begins to move – record the force meter reading, tabulate data, *repeat, calculate average.

[Or, use a bag to which washers may be added, attached to a cord and hanging over the end of *the bench to pull the block.]

quantities and the third unknown) – a three symbol triangle may simplify the maths.

Homework: Coursebook – Newton’s second Law

force (e.g. when a force acts on a body, it moves faster and kinetic energy increases)

• Introduce the relationship between energy transferred and work done.

• Define work done in terms of the applied force and the distance through which this ********force acts (Work done = force x distance)

• Use the work rule to calculate work / force / distance (given two quantities and the ********third unknown) – a three symbol triangle may simplify the maths

Homework: Coursebook – Work Done and Energy

6 – 7  Investigate and describe the pattern of results formed from graphing ************************the effects of applied forces on a spring.

Explore the relationships between science and technology by investigating the application of *science to technology and the impact of technology on science, e.g. Archimedes’ screw to *illustrate the principle of oits use in water irrigation or the use of springs and similar *propulsion devices in toys

Experiment 4: Stretching Springs

Hang a spring vertically using a clamp and stand. Add weights to the end of the spring, *measure the length of the spring after each additional weight is added. Calculate the *extension (Note: some initial weight will probably need to be added before the spring *stretches at all) Graph extension vs applied force. Interpret the graph, e.g. find the *extension for unit applied force or applied force per unit extension.

Investigate and understand the turning effect of a force.

Calculate the turning effect of a force = F x d where force (F) and distance (d) are *********at right angles.

Use the lever rule: F1d1 = F2d2 •

Discuss and brainstorm ideas about what causes things to turn about a pivot (fulcrum).

• Introduce the concept of the turning effect of a force (torque).

• Discuss the concept levers – to increase the turning effect, use a greater distance *******(e.g. a long crowbar) and/or a greater force (e.g. a heavier weight)

• Use the lever rule to calculate forces and distances at right angles to the applied ********force (given three quantities and the fourth unknown).